Heat oven to 450 degrees F.
Pierce each sausage with fork. Place sausages and water in large skillet. Bring to boiling over medium-high heat. Cover; cook 5 minutes; drain. Thinly slice sausage. Return sausages to skillet; saute until browned, for about 5 minutes.
Remove skillet from heat. Stir in pasta sauce and mushrooms.
Spoon one-quarter of sausage mixture onto each bread shell. Top each with 2 tablespoons mozzarella and 1 tablespoon Parmesan. Place on baking sheet.
Bake in 450 degree F oven 8 to 10 minutes or until hot and bubbly. Serve immediately. Makes 4 servings.